Tea polyphenols down-regulate JNK phosphorylation to inhibit neuron apoptosis in rats with cardiac arrest / 中华危重病急救医学

Objective To study the effect of tea polyphenols (TP) on c-Jun N-terminal kinase 1/2 (JNK1/2) phosphorylation and cell apoptosis in brain tissues in rats with cardiac arrest (CA) following cardiopulmonary resuscitation (CPR). Methods Healthy male Sprague-Dawley (SD) rats were randomly divided into sham group (n = 6), CA group (n = 12), and TP group (n = 12). The rats in CA and TP groups were induced ventricular fibrillation (VF) via esophagus stimulation with alternating current. Five minutes after CA, CPR was performed. Once restoration of spontaneous circulation (ROSC) was gained, normal saline (NS) and TP were injected intravenously in CA and TP groups with 10 mg/kg, respectively. Cortex of 6 rats in each group was harvested at 12 hours and 72 hours after ROSC. Cortex of sham group was harvested at 72 hours after operation without VF induction. The expressions of phosphorylated JNK1/2 (p-JNK1/2), JNK1/2, caspase-3, Bax and Bcl-2 were measured by Western Blot. Cell apoptosis was detected by TdT-mediated dUTP nick end labeling (TUNEL), and p-JNK/TUNEL double positive cells were detected by fluorescence double staining. Results Compared with sham group, the expressions of p-JNK, caspase-3 and Bax were increased, the expression of Bcl-2 was declined, and the apoptotic cells were significantly increased at 72 hours after ROSC in CA group. Compared with CA group, the phosphorylation of JNK was significantly declined at 12 hours and 72 hours after ROSC in TP group (the ratio of p-JNK1/2 and JNK1/2: 3.200±0.060 vs. 5.700±0.210, 1.400±0.060 vs. 5.400±0.090, both P < 0.05), the expressions of caspase-3 and Bax were decreased [caspase-3 (gray value): 42.00±5.23 vs. 54.00±7.84, 38.74±4.60 vs. 58.68±7.19; Bax (gray value): 38.04±6.21 vs. 68.76±6.08, 58.84±7.99 vs. 70.03±7.36, all P < 0.05], the expression of Bcl-2 was increased (gray value: 37.36±3.11 vs. 28.47±7.46, 48.78±6.55 vs. 29.54±3.13, both P <0.05); the cell apoptosis rate was reduced at 72 hours [(31.14±4.51)% vs. (45.87±3.95)%, P < 0.01], and p-JNK/TUNEL double positive cells/TUNEL cells ratio was significantly decreased (10.00±0.85 vs. 52.70±3.05, P < 0.01).Conclusion The inhibition of neuron apoptosis caused by TP after CPR in rats with CA is related to the inhibition of JNK1/2 phosphorylation.

Effect of hypothyroidism on oxidative stress, p38 and c-Jun N-terminal kinase mRNA expression in testicular mitochondria of male rats / 中华地方病学杂志

Objective To define the effect of hypothyroidism on oxidative stress,p38 and c-Jun N-terminal kinases (JNK) mRNA expression in testicular mitochondria of male rats,and to explore the mechanism of hypothyroidism on reproduction.Methods According to body weight (240-270 g),30 male Wistar rats were divided into control group (C group,1 ml/kg normal saline by intragastric administration),low-dose group (L group,0.1 mg/kg propylthiouracil 1 ml/kg by intragastric administration) and high-dose group (H group,10.0 mg/kg propylthiouracil 1 ml/kg by intragastric administration),10 rats in each group,body mass was weighed once every 3 days.After 60 days,all rats were killed.The levels of thyroid hormones [total triiodothyronine (TT3),total thyroxine (TT4),and thyroid stimulating hormone (TSH)] were measured by radioimmunoassay.The activities of superoxide dismutase (SOD) and catalase (CAT) in the testicular mitochondria were determined with spectrophotometric assay.The mRNA expression levels of p38 and JNK in testicular mitochondria were detected by real-time quantitative PCR.Results The weights of H group in 30 and 60 days [(265.73 ± 5.10),(253.72 ± 5.09) g] were significantly decreased in comparison with those of C group [(344.62 ± 4.69),(395.33 ± 8.36) g] and L group [(333.66 ± 3.53),(386.08 ± 7.70) g,P ＜0.05].While,testis organ coefficient of H group [(1.20 ± 0.05) g/100 g] were significantly increased compared with those of L group [(0.93 ± 0.03) g/100 g] and C group [(0.88 ± 0.03) g/100 g,P ＜ 0.05].The serum levels of TT3 [(0.39 ± 0.01) nmol/L] and TT4 [(15.47 ± 1.21) nmol/L] in H group were found to be significantly decreased compared with those of C group [(0.86 ± 0.07),(45.56 ± 1.52) nmol/L] and L group [(0.79 ± 0.06),(39.02 ± 1.33) nmol/L,P ＜ 0.05];whereas the level of TSH [(0.65 ± 0.09) mU/L)] was increased in comparison with those of the C group [(0.18 ± 0.06) mU/L] and L group [(0.27 ± 0.05) mU/L,P ＜ 0.05].In addition,the level of SOD in H group [(60.37 ± 3.14) U/mg prot] was decreased compared with that of C group [(75.18 ± 6.13) U/mg prot,P ＜ 0.05];the level of CAT in H group [(1.46 ± 0.25) U/mg prot] and L group [(1.67 ± 0.39) U/mg prot] decreased significantly compared with that of C group [(3.79 ± 0.44) U/mg prot,P ＜ 0.05].And compared with C (1.000 0 ± 0.000 0) and L (1.114 2 ± 0.124 1) groups,p38 mRNA expression in H group (1.387 4 ± 0.122 0) was significantly increased (P ＜ 0.05).However,there was no significant change in JNK mRNA expression between groups (F =0.95,P ＞ 0.05).Conclusion Hypothyroidism may induce oxidative stress of testicular mitochondria leading to the change of p38 cell signal path and then damage the reproductive system in male rats.

Effect of hypothyroidism on oxidative stress, p38 and c-Jun N-terminal kinase mRNA expression in testicular mitochondria of male rats / 中华地方病学杂志

Objective To define the effect of hypothyroidism on oxidative stress,p38 and c-Jun N-terminal kinases (JNK) mRNA expression in testicular mitochondria of male rats,and to explore the mechanism of hypothyroidism on reproduction.Methods According to body weight (240-270 g),30 male Wistar rats were divided into control group (C group,1 ml/kg normal saline by intragastric administration),low-dose group (L group,0.1 mg/kg propylthiouracil 1 ml/kg by intragastric administration) and high-dose group (H group,10.0 mg/kg propylthiouracil 1 ml/kg by intragastric administration),10 rats in each group,body mass was weighed once every 3 days.After 60 days,all rats were killed.The levels of thyroid hormones [total triiodothyronine (TT3),total thyroxine (TT4),and thyroid stimulating hormone (TSH)] were measured by radioimmunoassay.The activities of superoxide dismutase (SOD) and catalase (CAT) in the testicular mitochondria were determined with spectrophotometric assay.The mRNA expression levels of p38 and JNK in testicular mitochondria were detected by real-time quantitative PCR.Results The weights of H group in 30 and 60 days [(265.73 ± 5.10),(253.72 ± 5.09) g] were significantly decreased in comparison with those of C group [(344.62 ± 4.69),(395.33 ± 8.36) g] and L group [(333.66 ± 3.53),(386.08 ± 7.70) g,P ＜0.05].While,testis organ coefficient of H group [(1.20 ± 0.05) g/100 g] were significantly increased compared with those of L group [(0.93 ± 0.03) g/100 g] and C group [(0.88 ± 0.03) g/100 g,P ＜ 0.05].The serum levels of TT3 [(0.39 ± 0.01) nmol/L] and TT4 [(15.47 ± 1.21) nmol/L] in H group were found to be significantly decreased compared with those of C group [(0.86 ± 0.07),(45.56 ± 1.52) nmol/L] and L group [(0.79 ± 0.06),(39.02 ± 1.33) nmol/L,P ＜ 0.05];whereas the level of TSH [(0.65 ± 0.09) mU/L)] was increased in comparison with those of the C group [(0.18 ± 0.06) mU/L] and L group [(0.27 ± 0.05) mU/L,P ＜ 0.05].In addition,the level of SOD in H group [(60.37 ± 3.14) U/mg prot] was decreased compared with that of C group [(75.18 ± 6.13) U/mg prot,P ＜ 0.05];the level of CAT in H group [(1.46 ± 0.25) U/mg prot] and L group [(1.67 ± 0.39) U/mg prot] decreased significantly compared with that of C group [(3.79 ± 0.44) U/mg prot,P ＜ 0.05].And compared with C (1.000 0 ± 0.000 0) and L (1.114 2 ± 0.124 1) groups,p38 mRNA expression in H group (1.387 4 ± 0.122 0) was significantly increased (P ＜ 0.05).However,there was no significant change in JNK mRNA expression between groups (F =0.95,P ＞ 0.05).Conclusion Hypothyroidism may induce oxidative stress of testicular mitochondria leading to the change of p38 cell signal path and then damage the reproductive system in male rats.

Naloxone Postconditioning Alleviates Rat Myocardial Ischemia Reperfusion Injury by Inhibiting JNK Activity

To investigate the alteration of c-Jun N-terminal kinase (JNK) activity after myocardial ischemia reperfusion injury (MIRI) and further explore the effect of naloxone postconditioning on MIRI. Forty male Sprague Dawley rats were randomly divided into five groups: sham operation (sham, n=8); ischemia reperfusion (IR, n=8); IR+naloxone 0.5 mg/kg (Nal L, n=8); IR+naloxone 1.0 mg/kg (Nal M, n=8); IR+naloxone 2.0 mg/kg (Nal H, n=8). Pathological changes of myocardial tissue were visualized by HE staining. The expression of p-JNK, and the apoptosis of cardiomyocytes were investigated with Western blotting and the TUNEL assay, respectively. Irregular arrangement and aberrant structure of myocardial fibers, cardiomyocytes with granular or vacuolar degeneration, and inflammatory cells infiltrating the myocardial interstitial regions characterized MIRI in the IR group. Signs of myocardial injury and inflammatory infiltration were less prominent in the Nal-treated groups. The expression of p-JNK in the sham group and in all Nal-treated groups was significantly lower than that in the IR group (p<0.01). The apoptosis index of cardiomyocytes in the IR group was significantly higher than in the sham group (p< 0.01). The apoptosis indices of cardiomyocytes in all Nal-treated groups were significantly reduced to 55.4%, 26.2%, and 27.6%, respectively, of the IR group (p< 0.01). This study revealed that Naloxone postconditioning before reperfusion inhibits p-JNK expression and decreases cell apoptosis, thus alleviating MIRI.

Protection of quercetin against hyperbaric oxygen-induced apoptosis of human lens epithelial cell and its mechanism / 中华实验眼科杂志

Background Oxidative stress-induced apoptosis of human lens epithelial cells (LECs) is associated with c-Jun N terminal kinase (JNK) pathway.Quercetin possesses the antioxidation by inhibiting the JNK pathway.However,whether quercetin can protect LECs from the oxygen-induced damage is still not proved.Objective This study attempted to invatigate the effects and its mechanism of quercetin against hyperbaric oxygeninduced LECs apoptosis. Methods Human LECs line SRA01/04 was cultivated and passaged in MEM medium containing 10％ fetal bovine serum and 0.5％ non-essential amino acids for 2 hours,with or without 20 μmol/LSP600125 or 1 μmol/L quercetin prior to exposure to hyperbaric oxygen.Each exposure session remained 6 hours in 99％ O2 and 1％CO2 with a pressure chamber at 588 kPa.The viability of human LECs was detected by MTT.Cell apoptosis was assessed by flow cytometer using Annexin V-FITC apoptosis detection.The expression of JNK/p-JNK,c-Jun/p-c-Jun,caspase 3 and caspase 9 were detected by Western blot. Results LECs viability (A570 ) was 0.835 ±0.082,0.450±0.083,0.654±0.079,0.649±0.090 respectively in the blank control group,hyperbaric oxygen exposed group,hyperbaric oxygen+SP600125 group and hyperbaric oxygen+quercetin group.The A570 in the hyperbaric oxygen exposed group was significantly lower than the blank control group ( P =0.000),but those in hyperbaric oxygen + SP600125 group and hyperbaric oxygen+quercetin group were significantly higher than the hyperbaric oxygen exposed group ( P =0.003,0.002 ).The numbers of apoptosis cells were 3.17 ±0.74,19.77 ± 1.44,8.45 ±0.93,7.79 ±0.78 respectively in the blank control group,hyperbaric oxygen exposed group,hyperbaric oxygen+SP600125 group and hyperbaric oxygen+quercetin group.Apoptotic LECs were significantly increased in the hyperbaric oxygen exposed group compared with the blank control group ( P=0.000),but those in the hyperbaric oxygen+SP600125 group and hyperbaric oxygen+quercetin group were significantly reduced in comparison with hyperbaric oxygen exposed group (both P=0.000).In additional,expressions of p-JNK,p-c-Jun,caspase 3 and caspase 9 proteins in the cells were elevated in the hyperbaric oxygen exposed group compared with the blank control group (all P =0.000 ),however,those in the hyperbaric oxygen + SP600125 group and hyperbaric oxygen + quercetin group were declined when compared with the hyperbaric oxygen exposed group( all P＜0.05 ). Conclusions JNK pathway is involved in the apoptotic procedure of human LECs induced by oxygen stress.SP600125 and certain concentration of quercetin can interdict the JNK signal pathway and endogenous apoptosis of LECs and further alleviate hyperbaric oxygen-induced damage of LECs.

Celecoxib Attenuates Kainic Acid-induced Neuronal Cell Death Through Suppression of Microglial c-Jun N-terminal Kinase Phosphorylation

In the present study, neuroprotective property of celecoxib, a selective cyclooxygenase-2 (COX-2) inhibitor, and its underlying mechanism were examined in the animal model of kainic acid (KA)-induced excitotoxicity. KA, administered intracerebroventricularly (i.c.v.), induced marked neuronal cell death with concurrent microglial activation and subsequent induction of inducible nitric oxide synthase (iNOS) in the hippocampus. Histopathological analysis demonstrated that celecoxib (100 mg/kg), pre-treated 1 hr before or post-treated 2 hr after KA i.c.v. injection, significantly attenuated KA-induced death of pyramidal neurons in CA3 region. Celecoxib obviously suppressed KA-induced microglial activation and subsequent iNOS expression. KA- induced phosphorylation of c-Jun N-terminal kinases (JNK) was attenuated with celecoxib treatments. The results of the present study demonstrate that suppression of JNK phosphorylation by celecoxib contributes to its neuroprotective action against KA-induced excitotoxicity suggesting that celecoxib may be a potentially valuable in the treatment of acute brain pathologies associated with excitotoxic neuronal damage such as epilepsy, stroke, and traumatic brain injury.

Gene expression of mitogen-activated protein kinases in fetal skin at different developmental stages and its potentially biological siginificance / 解放军医学杂志

Objective To explore the change in gene expression of extracellular signal regulated protein kinase1 (erk1),erk2,p38MAPK and 3 c-Jun N- terminal kinases (jnk1,jnk2,jnk3) in fetal skin at different developmental stages and children skin. Methods After morphological characteristics of fetal skin at different developmental stages were examined histologically,gene expressions of erk1,erk2,p38MAPK,jnk1,jnk2 and jnk3 were determined with reverse transcription-polymerase chain reaction analysis (RT-PCR). Results Compared with early gestational fetal skin,the levels of gene expression of erk1 and erk2 showed no substantial change in late gestational fetal skin,while the contents of transcripts of p38MAPK and jnk1 were significantly decreased,the expressions of mRNA of jnk2 and jnk3 were obviously elevated. In children skin,gene expressions of erk2,p38MAPK and jnk1 were even more remarkably lowered. In contrary,gene expressions of jnk2 and jnk3 were marked enhanced. Conclusion The relative elevation of gene transcription of erk2 and p38MAPK and the inhibition of gene expression of jnk2 and jnk3 in fetal skin of earlier developmental stage might be related to fetal scarless healing.